EMI shielding film and front filter including the same in flat panel display device

ABSTRACT

A front filter being attached to a front surface of a flat panel display device includes a NIR (near infrared ray) blocking film for blocking the emission of near infrared rays to outside; an EMI (electromagnetic interference) shielding film for absorbing electromagnetic waves and for preventing the electromagnetic waves from being emitted to outside; a glass formed on a front surface of the EMI shielding film; and an antireflection coating for preventing incident rays from outside from reflecting back to the outside, in which the EMI shielding film includes a mesh unit formed of conductive meshes that are intersected with each other; and a mesh frame for surrounding the mesh unit to support the mesh unit and to define an effective display area on a screen.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates in general to an EMI(electromagnetic Interference) shielding film and a front filterincluding the same in a flat panel display device, more particularly, toan EMI shielding film and a front filter including the same in a flatpanel display device, wherein a manufacturing process for the EMIshielding layer is much simplified and thus, its cost of manufacture isconsiderably lowered.

[0003] 2. Discussion of the Background Art

[0004] Thanks to the technological developments in recent years, flatpanel displays have come into wide use. Typical examples of flat paneldisplays are LCDs (liquid crystal displays) and plasma display panels.

[0005] Particularly, plasma display panels (hereinafter referred to asPDPs) display images including characters or graphics by irradiatingphosphors out of 147 nm-ultraviolet rays that are generated by adischarge of different compositions of inert gas mixtures, such as,He+Xe, Ne+Xe or He+Ne+Xe.

[0006] The PDP technology is now at mass production stage, and recentadvances in PDP technologies made easier to manufacture slim PDPs and toprovide highly improved picture quality. Especially, in case of athree-electrode alternating current (AC) surface-discharge PDP, chargeparticles formed by a discharge (i.e. wall charges) are stacked on thesurface, which in turn protect electrodes from sputtering originated bythe discharge. Therefore, the three-electrode AC surface discharge PDPconsumes less voltage and has a long lifespan.

[0007]FIG. 1 is a perspective view of a discharge cell structure of arelated art PDP.

[0008] Referring to FIG. 1, a discharge cell of the three-electrode ACsurface-discharge PDP includes a scan electrode (Y) and a sustainelectrode (Z) formed on an upper substrate 10, and an address electrode(X) formed on a lower substrate 18. The scan electrode (Y) and thesustain electrode (Z) respectively includes transparent electrodes (12Yand 12Z), and bus electrodes (13Y and 13Z) formed on an edge of thetransparent electrodes (12Y and 12Z) and having a smaller line widththan that of the transparent electrodes (12Y and 12Z).

[0009] In general, the transparent electrodes (12Y and 12Z) are madefrom Indium-Tin-Oxide (ITO) and formed on the upper substrate 10. Thebus electrodes (13Y and 13Z) are typically made of metals like chrome(Cr) and formed on the transparent electrodes (12Y and 12Z). The majorfunction of the bus electrodes (13Y and 13Z) is reducing voltage dropcaused by the highly resistive transparent electrodes (12Y and 12Z).Also, an upper dielectric layer 14 and a protective film 16 are layeredon the upper substrate 10 on which the scan electrode (Y) and thesustain electrode (Z) are formed side by side. The charge particlesgenerated by a plasma discharge (i.e. wall charges) are stacked on theupper dielectric layer 14. The protective film 16 protects the upperdielectric layer 14 from damages caused by a sputtering during theplasma discharge, and improves the emission efficiency of secondaryelectrons. The protective film 16 is usually made from magnesium oxide(MgO).

[0010] A lower dielectric layer 22 and a barrier rib 24 are formed onthe lower substrate 18 provided with the address electrode (X). Thesurface of the lower dielectric layer 22 and the barrier rib 24 arecoated with fluorescent layers 26. The address electrode (X) is formedat right angles to the scan electrode (Y) and the sustain electrode (Z).The barrier rib 24 is formed in a strip or lattice pattern, and preventsultraviolet rays and visible rays generated by a discharge from beingleaked to the adjacent discharge cells.

[0011] The fluorescent layers 26 are excited by ultraviolet raysgenerated during the plasma discharge to generate one of visible rays inred, blue, or blue. A mixed inert gas is injected into a discharge spacedefined between the upper and lower substrates 10 and 18 and the barrierrib 24.

[0012] In the PDP with the above-described discharge cell structure, afront filter 30 is installed at the upper substrate 10, as shown in FIG.2, in order to shield electromagnetic wave and to prevent reflection ofexternal light.

[0013] There are two types of front filters 30: glass type front filtersand film type front filters. Both glass type front filters and film typefront filters are provided with an EMI shielding film 34, as shown inFIG. 3, to shield electromagnetic waves generated from the PDP.

[0014] The EMI shielding film 34 includes a mesh unit 38 provided withconductive meshes 36, a mesh frame 32 for surrounding the outside of themesh unit 38, and a black frame 40 superposed upon the mesh unit 38 andthe mesh frame 32.

[0015] The mesh unit 38 is formed of conductive meshes 36 beingintersected with each other. To create the conductive meshes 36, a meshmetal layer of silver (Ag) or copper (Cu) undergoes a photolithographyprocess. These intersected conductive meshes 36 provide square shapedholes tilted at a bias angle (θ) to transmit visible light raystherethrough.

[0016] The mesh frame 32 surrounds the outside of the mesh unit 38 tosupport the mesh unit 38. Also, the mesh frame 32 and a case (not shown)electrically connected to the mesh frame 32 are earthed to a groundvoltage, and absorb electromagnetic waves emitted from the PDP anddischarge them. In this manner, the electromagnetic waves are notemitted to outside. The mesh frame 32 is usually made from silver (Ag))or copper (Cu).

[0017] The black frame 40 defines an effective display area to makeoutlines of the screen visibly distinctive. The black frame 40 isrelatively broader than the mesh frame 30, and made from black ceramicmaterials.

[0018] A related art black frame for the glass type front filter wasformed by depositing a black ceramic material on the surface of a glasssubstrate (not shown) and then performing a patterning process thereon.However, because the related art method required an additional processfor forming the black frame, the overall process got more complicated.

SUMMARY OF THE INVENTION

[0019] An object of the invention is to solve at least the aboveproblems and/or disadvantages and to provide at least the advantagesdescribed hereinafter.

[0020] Accordingly, one object of the present invention is to solve theforegoing problems by providing an EMI shielding film and a front filterincluding the same in a flat panel display device, wherein amanufacturing process for the EMI shielding layer is much simplified andthus, its cost of manufacture is considerably lowered.

[0021] Another object of the invention is to provide an EMI shieldingfilm and a front filter including the same in a flat panel displaydevice, wherein the structure of the EMI shielding film is muchsimplified by removing a black frame that determines an effectivedisplay area on the screen.

[0022] The foregoing and other objects and advantages are realized byproviding a front filter in a flat panel display device, the frontfilter being attached to a front surface of the flat panel displaydevice and including a NIR (near infrared ray) blocking film forblocking the emission of near infrared rays to outside; an EMI(electromagnetic interference) shielding film for absorbingelectromagnetic waves and for preventing the electromagnetic waves frombeing emitted to outside; a glass formed on a front surface of the EMIshielding film; and an antireflection coating for preventing incidentrays from outside from reflecting back to the outside, wherein the EMIshielding film includes a mesh unit formed of conductive meshes that areintersected with each other; and a mesh frame for surrounding the meshunit to support the mesh unit and to define an effective display area ona screen.

[0023] The front filter further includes an antireflection coatingbetween the front surface of the flat panel display device and the NIRblocking film so that the antireflection coating prevents incident raysfrom outside from reflecting back to the outside.

[0024] Another aspect of the invention provides a front filter in a flatpanel display device, the front filter being attached to a front surfaceof the flat panel display device and including a NIR (near infrared ray)blocking film for blocking the emission of near infrared rays tooutside; an EMI (electromagnetic interference) shielding film forabsorbing electromagnetic waves and for preventing the electromagneticwaves from being emitted to outside; and an antireflection coating forpreventing incident rays from outside from reflecting back to theoutside, wherein the EMI shielding film includes a mesh unit formed bypatterning a two-layered base film of PEP (poly ethylene terephthalate)and metal foils; and a mesh frame for surrounding the mesh unit, themesh frame having a two-layered structure of PEP (poly ethyleneterephthalate) and metal foils.

[0025] Still another aspect of the invention provides an EMI(electromagnetic interference) shielding film of a flat panel displaydevice, in which the EMI shielding film includes: a mesh unit formed ofconductive meshes that are intersected with each other; and a mesh framefor surrounding the mesh unit to support the mesh unit and to define aneffective display area on a screen.

[0026] The mesh unit is formed by patterning a two-layered base film ofPEP (poly ethylene terephthalate) and metal foils.

[0027] The mesh frame has a two-layered structure including PEP (polyethylene terephthalate) and metal foils.

[0028] Additional advantages, objects, and features of the inventionwill be set forth in part in the description which follows and in partwill become apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objects and advantages of the invention may be realizedand attained as particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

[0030]FIG. 1 is a perspective view of a related art discharge cell in aplasma display panel;

[0031]FIG. 2 diagrammatically illustrates the installation of a frontfilter on an upper substrate in order to shield electromagnetic wavesand to prevent reflection of external light;

[0032]FIG. 3 illustrates a related art EMI (electromagneticinterference) shielding film;

[0033]FIG. 4 is a cross-sectional view of a related art EMI shieldingfilm;

[0034]FIG. 5 is a cross-sectional view of a front filter in accordancewith a first embodiment of the present invention;

[0035]FIG. 6 illustrates an EMI shielding film according to the presentinvention; and

[0036]FIG. 7 is a cross-sectional view of a PDP including a front filterin accordance with a second embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0037] The following detailed description will present preferredembodiments of the invention in reference to the accompanying drawingsFIGS. 5 to 7.

[0038]FIG. 5 is a cross-sectional view of a glass type front filter inaccordance with a first embodiment of the present invention.

[0039] Referring to FIG. 5, the glass type front filter 102 includes afirst antireflection coating 80 attached to a front surface of a glasssubstrate 82, an EMI shielding film 84, a NIR (near infrared ray)blocking film 86, and a second antireflection coating 88, the EMIshielding film 84, the NIR blocking film 86 and the secondantireflection coating 88 being adhered to a rear surface of the glasssubstrate 82 in cited order. The glass type front filter 102 shieldselectromagnetic waves generated to the front surface of a PDP 100,prevents reflection of external light, blocks near infrared rays, andcorrects colors.

[0040] The glass substrate 82 is made from a reinforced glass to supportthe glass type front filter 102 and to protect the front filter 102 andthe PDP 100 from damages caused by external impacts.

[0041] The first and second antireflection coatings 80 and 88 preventincident light rays from outside from being reflected back to theoutside and thus, improve contrast effects.

[0042] The EMI shielding film 84 absorbs electromagnetic waves generatedfrom the PDP 100, and shields the emission of the electromagnetic wavesto outside.

[0043] The NIR blocking film 86 absorbs near infrared rays at awavelength band of 800-1000 nm that are generated from the PDP 100, andblocks the emission of the near infrared rays to outside. This is howinfrared rays (approximately 947 nm) generated from a remote controllerare normally input to an infrared ray receiver built in the PDP set.Moreover, the NIR blocking film 87 includes a color correcting filmcontaining a color dye that increases color purity by adjusting orcorrecting colors. These films 80, 84, 86 and 88 are adhered to theglass substrate 82 through an adhesive or glue.

[0044] The glass type front filter 102 is installed at the front surfaceof the plasma display panel 100. The plasma display panel 100 includesan upper substrate 60 provided with a pair of sustain electrodes, and alower substrate 66 provided with an address electrode. As for the plasmadisplay panel 100, a barrier rib 74 is interposed between the upper andlower substrates 60 and 66.

[0045] As shown in FIG. 6, the EMI shielding film 84 according to thefirst embodiment of the invention includes a mesh unit 78 formed ofconductive meshes 76, and a mesh frame 72 for surrounding the outside ofthe mesh unit 78.

[0046] The mesh unit 78 is obtained by etching a two-layered base filmcomprised of PET (poly ethylene terephthalate) and metal foils. The meshunit 78 is formed of conductive meshes 76 in an intersection structure.To create the conductive meshes 76, a mesh metal layer of silver (Ag),copper (Cu), gold (Au) or aluminum (Al) undergoes a photolithographyprocess. These intersected conductive meshes 76 provide square shapedholes tilted at a bias angle (θ) to transmit visible light raystherethrough.

[0047] The mesh frame 72 surrounds the outside of the mesh unit 78 tosupport the mesh unit 78 and at the same time, to define an effectivedisplay area, thereby making outlines of the screen visibly distinctive.Also, the mesh frame 72 is a non-etched metal layer, which is formed bymasking the outside area of the mesh unit 78 under the etching process.

[0048] Therefore, the mesh frame 72 has a two-layered structure wherePEP (poly ethylene terephthalate) and metal foils are alternated witheach other.

[0049] Similar to the conductive meshes 76, the metal foil is made fromsilver (Ag), copper (Cu), gold (Au) or aluminum (Al).

[0050] More specifically speaking, the surface of the metal foil of themesh frame 72 is melanized. Preferably, the surface of the metal foil isany one of black, brown and gray colors.

[0051] The surface of the metal foil is melanized through anelectrochemical treatment, a selective printing, or being coating with acompound film. The electrochemical treatment involves oxidation orelectroless plating for example.

[0052] In other words, the surface of the metal foil can be oxidized orcoated with a compound film. Also, the surface of the metal foil can beprinted in ink or dye.

[0053] The surface treatment process on the metal foil is performedafter the mesh unit 78 and the mesh frame 72 are formed. It is alsopossible to treat the surface of base film first, the base film havingthe two-layered structure of PET and metal foil, and to form the meshunit 78 and the mesh frame 72 later.

[0054] In addition, the mesh frame 72 and a case (not shown)electrically connected to the mesh frame 72 are earthed to a groundvoltage, and absorb electromagnetic waves emitted from the PDP anddischarge them. This is how the mesh frame 72 prevents theelectromagnetic waves from being emitted to outside.

[0055] The mesh frame 72 has the same width with the related art blackframe.

[0056]FIG. 7 is a cross-sectional view of a PDP including a film typefront filter according to the second embodiment of the invention.

[0057] As shown in FIG. 7, the film type front filter 104 includes a NIR(near infrared ray) blocking film 86, an EMI shielding film 84, and anantireflection coating 80, the NIR blocking film 86, the EMI shieldingfilm 84, and the antireflection coating 80 being adhered to an uppersubstrate 60 of a PDP 100 in cited order. Since the NIR blocking film 86and the antireflection coating 80 are already explained in detail withreference to FIG. 5, further description will not be provided here.

[0058] As illustrated in FIG. 6, a mesh frame 72 of the EMI shieldingfilm 84 surrounds the outside area of the mesh unit 78 to support themesh unit 78 and at the same time, to define an effective display area,thereby making outlines of the screen visibly distinctive.

[0059] In addition, the mesh frame 72 and a case (not shown)electrically connected to the mesh frame 72 are earthed to a groundvoltage, and absorb electromagnetic waves emitted from the PDP anddischarge them. This is how the mesh frame 72 prevents theelectromagnetic waves from being emitted to outside.

[0060] The mesh frame 72 has the same width with the related art blackframe. To define the effective display area, a metal layer made from Ag,Cu, Au or Al for example undergoes a patterning process, and the surfaceof the metal foil is melanized. To be more specific, the surface of themetal foil is melanized through an electrochemical treatment, aselective printing, or being coating with a compound film. Theelectrochemical treatment involves oxidation or electroless plating forexample.

[0061] Because the film type front filter 104 according to the secondembodiment of the invention is attached to the upper substrate 60 of thePDP 100, it does not require the glass substrate 82 that was used forthe glass type front filter 102 of FIG. 5. Therefore, the film typefront filter 104, compared to the glass type front filter 104, is moreeffective for manufacturing slimmer and lighter PDP sets.

[0062] In conclusion, the present invention has simplified themanufacture process and reduced the cost of manufacturing involved inthe EMI shielding film and the front filter including the same.

[0063] While the invention has been shown and described with referenceto certain preferred embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

[0064] The foregoing embodiments and advantages are merely exemplary andare not to be construed as limiting the present invention. The presentteaching can be readily applied to other types of apparatuses. Thedescription of the present invention is intended to be illustrative, andnot to limit the scope of the claims. Many alternatives, modifications,and variations will be apparent to those skilled in the art. In theclaims, means-plus-function clauses are intended to cover the structuresdescribed herein as performing the recited function and not onlystructural equivalents but also equivalent structures.

What is claimed is:
 1. A front filter in a flat panel display device,the front filter being attached to a front surface of the flat paneldisplay device and comprising a NIR (near infrared ray) blocking filmfor blocking the emission of near infrared rays to outside; an EMI(electromagnetic interference) shielding film for absorbingelectromagnetic waves and for preventing the electromagnetic waves frombeing emitted to outside; a glass formed on a front surface of the EMIshielding film; and an antireflection coating for preventing incidentrays from outside from reflecting back to the outside, wherein the EMIshielding film comprising: a mesh unit formed of conductive meshes thatare intersected with each other; and a mesh frame for surrounding themesh unit to support the mesh unit and to define an effective displayarea on a screen.
 2. The front filter according to claim 1 furthercomprises an antireflection coating between the front surface of theflat panel display device and the NIR blocking film so that theantireflection coating prevents incident rays from outside fromreflecting back to the outside.
 3. The front filter according to claim1, wherein the conductive meshes of the mesh unit are formed by etchinga two-layered base film comprised of PET (poly ethylene terephthalate)and metal foils.
 4. The front filter according to claim 1, wherein themesh frame is made from one of silver (Ag), copper (Cu), gold (Au), andaluminum (Al).
 5. The front filter according to claim 1, wherein themesh frame is formed by oxidizing a metal foil.
 6. The front filteraccording to claim 1, wherein the mesh frame is formed by coating ametal foil with a compound film.
 7. The front filter according to claim1, wherein the mesh frame is formed by melanizing the surface of a metalfoil through an electroless plating process.
 8. The front filteraccording to claim 1, wherein the mesh frame is formed by printing thesurface of a metal foil in ink or dye.
 9. A front filter in a flat paneldisplay device, the front filter being attached to a front surface ofthe flat panel display device and comprising a NIR (near infrared ray)blocking film for blocking the emission of near infrared rays tooutside; an EMI (electromagnetic interference) shielding film forabsorbing electromagnetic waves and for preventing the electromagneticwaves from being emitted to outside; and an antireflection coating forpreventing incident rays from outside from reflecting back to theoutside, wherein the EMI shielding film comprising: a mesh unit formedby patterning a two-layered base film comprising PEP (poly ethyleneterephthalate) and metal foils; and a mesh frame for surrounding themesh unit, the mesh frame having a two-layered structure comprised ofPEP (poly ethylene terephthalate) and metal foils.
 10. The frontaccording to claim 9 further comprises an antireflection coating betweenthe front surface of the flat panel display device and the NIR blockingfilm so that the antireflection coating prevents incident rays fromoutside from reflecting back to the outside.
 11. An EMI (electromagneticinterference) shielding film of a flat panel display device, comprising:a mesh unit formed of conductive meshes that are intersected with eachother; and a mesh frame for surrounding the mesh unit to support themesh unit and to define an effective display area on a screen.
 12. TheEMI shielding film according to claim 11, wherein the mesh unit isformed by patterning a two-layered base film comprised of PEP (polyethylene terephthalate) and metal foils.
 13. The EMI shielding filmaccording to claim 11, wherein the mesh frame has a two-layeredstructure comprising PEP (holy ethylene terephthalate) and metal foils.